Yes, babies can feel pain during birth. Full-term newborns have the neural wiring needed to detect and process painful stimuli, and brain imaging confirms that their cortex responds to painful events with distinct, measurable activity. What’s less clear is how a newborn’s experience of pain compares to an adult’s, partly because babies are flooded with natural painkillers during labor that appear to blunt the intensity considerably.
When Pain Pathways Develop
The ability to sense pain builds gradually throughout pregnancy. Peripheral nerve endings called nociceptors, the body’s pain detectors, first appear around the mouth at 7.5 weeks of gestation. They spread to the hands by 10 weeks and cover most of the body by 14 to 15 weeks. But having sensors in the skin is only part of the picture. For a fetus to consciously experience pain, signals from those sensors need to reach the brain’s cortex through a relay station called the thalamus.
Those critical connections between the thalamus and cortex start forming between 23 and 30 weeks of gestation. A systematic review published in JAMA concluded that the capacity for functional pain perception in preterm neonates probably does not exist before 29 or 30 weeks, with the earliest reliable evidence of those connections appearing around week 29. By full term (37 weeks and beyond), the system is operational. EEG recordings show that a specific brain wave pattern tied to pain processing, distinct from the response to simple touch, begins appearing reliably from about 37 weeks of age.
What Brain Scans Actually Show
Researchers have directly measured how newborn brains respond to painful versus non-painful touch using EEG and near-infrared spectroscopy, a technique that tracks blood flow changes in the brain. When newborns received a clinically required heel lance (a small prick to draw blood), their brains produced a hemodynamic response ten times larger than when they received a gentle, non-painful touch. The painful stimulus also triggered a unique electrical signature in the brain that did not appear with harmless contact. These are not just reflexes. They represent cortical processing, meaning the signal reaches the thinking and feeling parts of the brain, not just the spinal cord.
The Body’s Built-In Pain Relief
Babies don’t go through birth unprotected. During labor, both the mother and fetus release a surge of natural opioids called beta-endorphins. Umbilical cord blood contains significantly higher concentrations of these painkillers than the mother’s own blood, with cord levels averaging around 196 pg/ml compared to 128 pg/ml in the mother. This holds true regardless of how the baby is delivered.
Labor also triggers a massive release of stress hormones, primarily adrenaline and noradrenaline. While these might sound harmful, they serve several survival functions. They stimulate the lungs to absorb fluid, which is essential for a baby’s first breaths. They help release surfactant, a substance that keeps the tiny air sacs in the lungs from collapsing. They stabilize heart function and metabolism and provide protection against low oxygen levels. Babies delivered by planned cesarean section before labor begins have significantly lower levels of these hormones and face a higher risk of breathing problems, sometimes called “wet lungs,” because the fluid clearance process never fully kicked in.
So the stress of birth, while intense, is not purposeless suffering. It activates protective systems that help the baby transition from living in fluid to breathing air.
Vaginal Birth vs. Cesarean Delivery
The physical compression and pressure of vaginal delivery produces a stronger hormonal stress response than cesarean birth. Babies born vaginally have higher cortisol levels than those born by cesarean, and this difference persists in a surprising way. Research tracking infants through six months of age found that cesarean-delivered babies had lower baseline cortisol and a weaker cortisol response to a routine vaccination compared to vaginally delivered babies. This wasn’t explained by whether the cesarean was planned or emergency, or whether the mother experienced any labor beforehand.
This doesn’t mean vaginal birth is more “traumatic.” Cortisol is not purely a pain signal. It plays a central role in alertness, lung maturation, and metabolic adaptation. Higher cortisol at birth reflects a system preparing the body for life outside the womb. The lower cortisol response months later in cesarean-born babies may reflect differences in how the stress-response system was calibrated during birth itself.
How Clinicians Assess Newborn Pain
Since babies can’t describe what they feel, hospitals use standardized pain scales based on observable behavior. The Neonatal Infant Pain Scale (NIPS) scores six indicators: facial expression (relaxed versus grimacing), crying (none, whimpering, or vigorous), breathing pattern changes, arm tension, leg tension, and overall state of arousal. A baby showing multiple signs, such as rigid limbs, grimacing, vigorous crying, and irregular breathing, scores higher and is considered to be in pain.
Other scales like the COMFORT-B assess alertness, calmness, muscle tone, and body movement over a two-minute observation window. These tools were developed because, for decades, the medical community underestimated or dismissed newborn pain. Until 1987, it was common for surgery on newborns to be performed with minimal or no anesthesia. That year, the American Academy of Pediatrics formally recognized that neonates do feel pain and that anesthesia should be used for surgical procedures, just as it would for any other patient.
What Helps After Birth
Skin-to-skin contact immediately after delivery appears to have a genuine calming effect on the newborn stress response. In preterm infants, a session of skin-to-skin contact with the mother reduced beta-endorphin levels by about 74%, a significant drop that did not occur during a control period without contact. Cortisol levels also fell. The drop in natural painkillers likely reflects that the baby’s body is detecting less need for them, not that the baby is in more distress.
Breastfeeding within the first hour has a similar soothing effect and is often used in neonatal units as a non-drug comfort measure during minor procedures like blood draws. The combination of warmth, physical contact, suckling, and the taste of breast milk activates multiple calming pathways in the newborn brain simultaneously.
What This Means in Practical Terms
A full-term baby going through vaginal birth has a functioning pain system, but one that is heavily buffered by natural opioids and stress hormones. The experience is almost certainly not comparable to what an adult would feel if subjected to the same physical forces. The brain’s pain-processing networks are present but still maturing, the body is flooded with its own analgesics, and the hormonal surge that accompanies labor serves critical survival functions that make the transition to independent life possible. Birth is stressful for the baby in a measurable, biological sense. But the stress appears to be a feature of the process, not a flaw in it.